1. Technical Field of the Invention
The present invention relates to an electro-optical device comprising color filters composed of R (red), G (green), and B (blue) colored layers and a plurality of spacers formed by a pattern-forming method such as a photolithography process, and to an electronic apparatus. The present invention also relates to a method of manufacturing the electro-optical device.
2. Description of the Related Art
In general, in a liquid crystal device, a liquid crystal layer is interposed between a pair of substrates, the alignment of liquid crystal molecules in the liquid crystal layer is controlled in each display dot, which is a minimum unit of display, and light passing through the liquid crystal layer is modulated in each display dot by the liquid crystal molecules, thereby displaying an image, such as a character, number, or figure, on the downstream side of the liquid crystal layer in the propagating direction of the light.
In such a liquid crystal device, in order to form the liquid crystal layer, it is necessary to form a gap, that is, a so-called cell gap between the pair of substrates. In order to form the cell gap, spacers that are spherical members are dispersed on one of the pair of substrates, and the pair of substrates is attached to each other.
In addition, recently, a structure in which a plurality of protruding spacers are formed on one substrate by a pattern-forming method using a photolithography process and the pair of substrates are attached to each other with the spacers interposed therebetween has been proposed. The spacers are also referred to as columnar spacers.
When the spacers are formed by a photolithography process in this way, the alignment of liquid crystal molecules is disturbed around the spacers, and thus a display defect, such as light leakage, may easily occur. Therefore, the spacers are mainly formed in a light-shielding region that is a non-display region, that is, a so-called black mask region.
In addition, in the liquid crystal device having the spacers. formed by the photolithography process, after a plurality of spacers are formed on a substrate, an alignment film for determining the alignment of the liquid crystal molecules is provided on the spacers by a printing method. Then, an alignment process, for example, rubbing is performed on the alignment layer. When rubbing is performed, it is difficult to perform uniform rubbing if the alignment layer protrudes from the spacers. For example, a region in which rubbing is insufficiently performed occurs on the downstream side of the spacers in the rubbing direction.
Several methods have been proposed to obtain a display with high contrast even when a region subjected to insufficient rubbing occurs due to the existence of the spacers. For example, there has been known a technique of preventing deterioration of the display quality by forming a black mask region, which is a region that does not contribute to display, so as to correspond to the region subjected to insufficient rubbing. In addition, a liquid crystal device in which spacers are formed such that red pixels or blue pixels are situated on the downstream side of the spacers in the rubbing direction has been known.
However, when a display screen of a liquid crystal device is pressed, display may be disturbed due to a variation of the cell gap. In addition, on occasion, the panel structure of the liquid crystal device may be damaged. In order to prevent the above problems, it is effective to increase the number of spacers or the cross-sectional area of each spacer. However, when the number of spacers or the cross-sectional area of each spacer increases without any restriction, the following serious problems arise.
When manufacturing a liquid crystal device, for example, a series of processes are preformed: color filters are formed on one of a pair of substrates, spacers are formed on the other one of the pair of substrates, the substrates are attached to each other with the spacers interposed therebetween, liquid crystal is injected into a gap between the substrates maintained by the spacers, and a liquid crystal layer is formed. In this case, when the pair of substrates is attached to each other, a positional deviation may occur between the substrates in plan view. In this case, the spacers to be originally situated in a region where a black mask is formed, that is, in a light-shielding region, may be situated in the colored layers of the color filters. As result, the display quality, such as the contrast, may deteriorate.
In addition, there is another liquid crystal device in which color filters and spacers are formed on the same one of a pair of substrates. When manufacturing such a liquid crystal device, the color filters are formed at predetermined positions based on alignment marks formed at appropriate positions on the substrate, and then the spacers are formed at predetermined positions based on the same alignment marks or other alignment marks. In this case, when the positions of the spacers are determined based on the alignment marks, a positional deviation may occur. Then, the spacer to be originally formed in the black mask region may be situated in the colored layers of the color filters. Therefore, the display quality, such as the contrast, may deteriorate.
The present invention is designed to solve such problems. Accordingly, an object of the present invention is to provide an electro-optical device including a liquid crystal device having spacers formed by a photolithography process and colored layers constituting color filters, wherein in the electro-optical device, resisting pressure is maintained at a high level when a display screen of the electro-optical device is pressed, and the deterioration of the display quality is prevented even when an assembly error occurs in attaching the substrates or a positional deviation occurs during alignment.